Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Exxon catalytic coal gasification process: predevelopment program. Annual report, July 1976--June 1977

Technical Report ·
DOI:https://doi.org/10.2172/6074818· OSTI ID:6074818

The Exxon Catalytic Gasification Process combines the use of alkali metal gasification catalyst with a novel processing sequence which maximizes the benefits which can be derived from use of the catalyst. The principal reasons for using alkali metal gasification catalysts are that they increase the rate of steam gasification, prevent agglomeration of caking coals, and promote the achievement of gas compositions closely approaching gas phase methanation equilibrium. The process combines a relatively low gasifier temperature of about 1300/sup 0/F with separation of synthesis gas (CO + H/sub 2/) from the product methane and recycle of the synthesis gas to the gasifier. Thus the only net products from gasification are CH/sub 4/, CO/sub 2/, and small quantities of H/sub 2/S and NH/sub 3/. The resulting overall gasification reaction can be represented as follows: Coal + H/sub 2/O ..-->.. CH/sub 4/ + CO/sub 2/. Since this reaction is essentially thermoneutral, major heat input to the gasifier is not required. A simplified flow plan for the Exxon Catalytic Gasification Process is shown. No significant tars or oils are produced. Following heat recovery and water scrubbing, the product gas is treated in a series of separation steps including acid gas scrubbing to remove CO/sub 2/ and H/sub 2/S, and cryogenic fractionation to separate product methane from synthesis gas. The synthesis gas is combined with feed steam, preheated to approximately 150/sup 0/F above the gasification temperature and recycled to the gasifier. Although there is no heat required for the gasification reactions, some small amount of heat input is required to heat up the feed coal, vaporize residual water and provide for gasifier heat losses.

Research Organization:
Exxon Research and Engineering Co., Baytown, TX (USA)
OSTI ID:
6074818
Report Number(s):
FE-2369-20
Country of Publication:
United States
Language:
English